Anti-pdef antibodies and uses thereof

ABSTRACT

The present invention relates to an isolated antibody or antigen-binding fragment thereof that specifically binds with high affinity to at least a portion of a segment of human prostate-derived Ets transcription factor (PDEF). The anti-PDEF antibody of the present invention is effective in prognostic and diagnostic assays for detecting PDEF with immunohistochemistry. The present invention also relates to methods of making the anti-PDEF antibody disclosed herein. The present invention further relates to vaccines against cancers associated with positive expression of PDEF, as well as methods for treating those cancers. Vectors, diagnostic kits, and hybridomas are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/342,037, filed Dec. 22, 2008, which issued as U.S. Pat. No. 8,257,716on Sep. 4, 2012, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/015,925, filed Dec. 21, 2007, the disclosures ofwhich are hereby incorporated by reference herein in their entirety.

GOVERNMENT RIGHTS STATEMENT

The present invention was made with U.S. Government support underNational Cancer Institute Grant No. CA86164 and Department of DefenseGrant No. BC045095. The U.S. Government has certain rights in theinvention.

FIELD OF THE INVENTION

The present invention relates to an isolated antibody or antigen-bindingfragment thereof that specifically binds with high affinity to at leasta portion of a segment of human prostate-derived Ets transcriptionfactor (PDEF). The present invention also relates to vaccines, vectors,and methods of using the anti-PDEF antibody in prognostic and diagnosticmethods.

BACKGROUND OF THE INVENTION

As used herein, certain citations to references are indicated asnumerals or alphanumerical symbols in parentheticals, and are furtherdescribed in the “References Cited” listing contained herein.

Breast cancer is the most common malignancy in women, as about a millionnew cases of this cancer are diagnosed worldwide each year, and 375,000women die from it (B1). Although early detection through screeningmammography has increased the proportion of in situ and early stagebreast cancers that have excellent prognosis, mortality rates fromrecurrent and late stage breast cancers have not declined significantly(B2). Consequently, conventional therapies including surgery, radiationand chemotherapy need to be supplemented with novel therapies thattranslate into significant improvement in the clinical outcome for mostbreast cancer patients.

Similarly, prostate cancer is the most commonly diagnosed malignancy inmen, with about 220,000 new cases of prostate cancer diagnosed each yearin the U.S. alone. Of these, approximately two-thirds are treated bysurgery or radiation therapy, and 40% of the treated men will eventuallyrelapse, as characterized by rising levels of prostate specific antigen(B3, B4). Relapsed advanced and metastatic prostate cancer remains theprimary cause of death from this cancer, since current systemic hormonaland chemotherapy approaches are only marginally successful (B5).Consequently there is an urgent need for novel therapies to treatadvanced prostate cancer.

Further, despite intense therapeutic efforts, ovarian cancer remains thefifth leading cause of death among women in the United States (B6).Serous adenocarcinomas account for approximately 80% of all ovariancancers and are considered surface epithelial tumors (B7). Early stageepithelial ovarian cancer has an excellent prognosis with 5 yearsurvival rates above 90%. However, about 80% of patients with ovariancancer initially present with metastatic disease, resulting in 5 yearsurvival rates of only 10-20%. Following primary therapy, as many as 70%of women with advanced ovarian cancer will experience a recurrence oftheir disease. Novel therapies to eradicate the residual or recurrentmalignancy are critically needed to increase the unacceptable lowsurvival rates (B8).

Prostate derived Ets factor (PDEF) belongs to the Ets family oftranscription factors that play an important role in normal as well asneoplastic development (B9-B13). However, despite such promise,knowledge in the art about the characteristics of PDEF expression inhuman cancer remains limited.

PDEF was originally described as a novel prostate specific transcriptionfactor based on its prostate restricted expression in normal humantissues and its ability to induce the expression of prostate specificantigen (PSA) in tumor cell lines (A1). Shortly thereafter, it was shownthat (i) PDEF mRNA was frequently over expressed in primary breasttumors from patients, and (ii) among normal tissues, it showedexpression in the trachea/bronchus tissues in addition to the normalprostate tissue (A2). In contrast, other normal tissues including brain,heart, kidney, liver, lung, skeletal muscle, spleen, testis, and uteruswere negative for PDEF expression (A2). More recently, a screen of amuch larger collection of breast tumors and normal human tissues hasconfirmed the Inventor's findings and showed that roughly 75% of newlydiagnosed breast tumors show varying level of over expression of PDEF(A3). These observations suggested a role for PDEF in breast andprostate cancer progression.

A major deficiency of the above studies was that all the work wasperformed at the PDEF mRNA level, and in the absence of any evidenceshowing correspondence between PDEF mRNA and PDEF protein expression, aputative role for PDEF in tumor progression remained speculative, atbest. Moreover, two groups prepared antibodies against the full-lengthPDEF protein and reported that PDEF protein was strongly expressed innormal breast (A4) and prostate (A5) tissues, but only weakly in thetumor tissues. The latter results were diametrically opposite to thosereported for PDEF mRNA (A1-3). One explanation for such discrepantreports of PDEF mRNA and protein expression was that the antibodies tofull-length PDEF proteins were not specific for PDEF, and may becross-reacting with other members of the Ets transcription factor familyto which PDEF belongs. Specifically, there are two structural motifswithin the sequence of PDEF, called “Pointed domain” and DNA binding“Ets” domain, and these show high level of sequence homology withsimilar structural motifs present in other members of the Ets factorfamily (FIG. 1), and these appeared likely as targets for cross-reactionwith anti-PDEF antibodies.

One approach to investigating PDEF has involved the attempt to developantibodies with the bind specifically to PDEF with high affinity.However, prior to the present invention, no such high affinity anti-PDEFantibody had been described that could be used for clinical diagnostics.For example, previously, anti-PDEF antibodies have been generatedagainst the full-length PDEF protein (4). While these antibodies reactedwith PDEF in the Western blot assay, the specificity of their reactivityin the immunohistochemistry assay for screening PDEF expression inpatient's samples has remained suspect; since those antibodies reactedstrongly with normal breast tissues and weakly with breast tumorstissue, a finding contradictory to previously reported PDEF mRNAexpression data (3, 22, A3). A likely explanation for suchuncharacteristic reactivity of antibodies against full-length PDEF isthe homology between PDEF and other Ets factors in the Pointed domainand DNA binding Ets domain (see FIGS. 1B and 1C respectively). Such highdegree of homology within these domains suggested the potential forcross-reaction of the antibodies with other members of the Etstranscription factor family. In fact, the Inventor's lab also previouslyprepared antibody against the full-length PDEF protein and found that itreacted uncharacteristically strongly with normal breast tissue.

Antibodies to fragments of PDEF have also been described, but none ofthese antibodies was shown to have high affinity to PDEF. For example,antibodies to amino acid residues 1-104 of PDEF were described byGhadersohi et al. (A7, A8). However, like previously reported antibodiesto full-length PDEF, the antibodies described by Ghadersohi et al. alsoreacted strongly with normal breast and ovarian tissues, and weakly ornot at all with tumor tissues, showing a lack of specificity for PDEF inthe immunohistochemical assay.

It is shown that about 80% of primary breast tumors, 70% of primaryprostate tumors, and 30 to 35% of primary ovarian tumors showover-expression of PDEF protein in tumor tissues in comparison to normaltissues (1, 2). Further, (i) transfection of PDEF into a low-malignancybreast epithelial cell line induced its accelerated tumor growth in vivoin immunodeficient mice; and (ii) meta analysis of the GEO and Oncominedatabases that contain the global gene expression data from breasttumors and the linked clinical outcome data for patients showed thathigh PDEF expression correlates with poor overall survival for patientswith estrogen receptor-positive (ER⁺) breast tumors. In prostate canceras well, high PDEF expression was found to correlate with earlybiochemical PSA failure, a surrogate marker of cancer recurrence anddisease progression.

Despite considerable progress in early detection of breast and prostatecancers, mortality from advanced and metastatic disease has not declinedsignificantly over the past several decades. Further, even with theknowledge of PDEF's role in various types of cancers, prognostic,diagnostic, and treatment methods that directed to detection of PDEF orblocking of PDEF have not been forthcoming.

The present invention is directed to the deficiencies in the art.

SUMMARY OF THE INVENTION

In one aspect, the present invention relates to an isolated antibody orantigen-binding fragment thereof that specifically binds with highaffinity to at least a portion of a segment of a human prostate-derivedEts transcription factor (referred to herein as “PDEF”). Suitablesegments of PDEF can include, but are not limited to, the following: (i)amino acid residues 1-104 of SEQ ID NO:1; (ii) amino acid residues105-141 of SEQ ID NO:1; or (iii) amino acid residues 214-247 of SEQ IDNO:1.

In another aspect, the present invention relates to a hybridoma thatproduces the antibody according to the present invention, particularlyan antibody of the present invention where the antibody is a monoclonalantibody.

In yet another aspect, the present invention relates to a diagnostickit. This kit can include, without limitation: (i) a first containercontaining the antibody or antigen-binding fragment thereof, asmentioned herein; and (ii) a second container for detection of theantibody or antigen-binding fragment thereof, wherein the secondcontainer comprises a label. The diagnostic kit of the present inventioncan further include at least one third container selected from the groupconsisting of a wash reagent and a detection reagent.

In one aspect, the present invention relates to a vaccine for immunizingan individual against a cancer disease associated with positiveexpression of PDEF. As used herein, a cancer disease associated withpositive expression of PDEF includes, without limitation, breast cancer,prostate cancer, ovarian cancer, endometrial cancer, colon cancer, andcervical cancer. The vaccine includes a polypeptide corresponding to aPDEF fragment that is effective to induce an immune response to PDEF inthe individual. Suitable PDEF fragments can include, for example, a PDEFfragment having (i) an amino acid sequence corresponding to SEQ ID NO:2,SEQ ID NO:3, and/or SEQ ID NO:4; (ii) an amino acid sequence having atleast 8 continuous residues from SEQ ID NO:2, SEQ ID NO:3, or SEQ IDNO:4; or (iii) two or more amino acid sequences having at least 8continuous residues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.In addition to the PDEF fragment, the vaccine of the present inventioncan include a pharmacologically acceptable carrier or adjuvant.

In still another aspect, the present invention relates to a method forimmunizing an individual against a cancer disease associated withpositive PDEF expression. This method involves administering the vaccineof the present invention into the individual. Suitable individuals forPDEF immunization can include, without limitation, a individual that ishigh risk for, predisposed to, susceptible to, and/or diagnosed withsaid cancer disease associated with positive PDEF expression. The methodis effective to immunize against such diseases that include, but are notlimited to, breast cancer, prostate cancer, ovarian cancer, endometrialcancer, colon cancer, and/or cervical cancer.

In a further aspect, the present invention relates to a viral or plasmidexpression vector. This viral or plasmid expression vector includes anucleotide sequence that is operably linked to a promoter and thatencodes an antigen. Suitable antigens can include, without limitation, aPDEF fragment having the following: (i) an amino acid sequencecorresponding to SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4; (ii) anamino acid sequence having at least 8 continuous residues from SEQ IDNO:2, SEQ ID NO:3, or SEQ ID NO:4; or (iii) two or more amino acidsequences having at least 8 continuous residues from SEQ ID NO:2, SEQ IDNO:3, and/or SEQ ID NO:4.

The present invention also relates to a vaccine having (a) theexpression vector of the present invention discussed herein and (b) apharmacologically acceptable carrier or adjuvant.

The present invention also relates to a method for immunizing anindividual against a cancer disease associated with positive PDEFexpression by administering this vaccine to the individual, where theindividual is at high risk for, predisposed to, susceptible to, and/ordiagnosed with said cancer disease associated with positive PDEFexpression. The method is effective to immunize against such diseasesthat include, but are not limited to, breast cancer, prostate cancer,ovarian cancer, endometrial cancer, colon cancer, and/or cervicalcancer.

In another aspect, the present invention relates to a method ofpreparing a polyclonal antibody that specifically binds with highaffinity to PDEF. This methods involves immunizing an animal with a PDEFfragment having an amino acid sequence corresponding to SEQ ID NO:2, SEQID NO:3, and/or SEQ ID NO:4 under conditions effective to elicit anantibody response. The antibodies are isolated from the animal.Thereafter, this method involves screening the isolated antibodies usingan immunohistochemical assay to identify a polyclonal antibody thatspecifically binds with high affinity to PDEF. The polyclonal antibodyif then isolated. The present invention also relates to a polyclonalantibody produced by this method.

In still another aspect, this invention relates to a method forgenerating a monoclonal antibody that specifically binds with highaffinity to PDEF. This method involves administering to an animal anamount of an immunogenic composition that includes a PDEF segmenteffective to stimulate a detectable immune response. A suitable PDEFsegment can include, without limitation, an amino acid sequencecorresponding SEQ ID NO:2, SEQ ID NO:3, and SEQ ID NO:4. Thereafter,antibody-producing cells are obtained from the animal and theantibody-producing cells are fused with myeloma cells to obtainantibody-producing hybridomas. A hybridoma is selected that produces amonoclonal antibody that specifically binds with high affinity to PDEF,where the high affinity is confirmed using an immunohistochemical assay.Thereafter, the selected hybridoma is cultured in a cell culture thatproduces the monoclonal antibody. The monoclonal antibody is thenobtained from the cell culture.

The present invention also relates to a method of determining whether ahuman subject is susceptible to a type of cancer characterized bypositive expression of PDEF. This method involves obtaining a tissuesample from a subject, where the tissue sample is suspected of being acancer tumor tissue. The tissue sample is then contacted with theantibody or antigen-binding fragment thereof according to the presentinvention, and under conditions effective to allow for measuring thelevel of PDEF expression in the tissue sample. Under this method,measuring the level of PDEF expressed in the tissue sample using animmunohistochemical assay, whereby positive expression of PDEF indicatesthat the subject is susceptible to a type of cancer characterized bypositive expression of PDEF.

In another aspect, the present invention relates to a method ofprognostic stratification of a cancer patient for targeted therapeuticcancer treatment. This method involves obtaining a tissue sample fromthe cancer patient, where the tissue sample is suspected of includingcancer tumor tissue. The tissue sample is contacted with the antibody orantigen-binding fragment thereof of the present invention so as to beeffective to allow for measuring the level of PDEF expression in thetissue sample. The level of PDEF is then measured in the tissue sampleusing an immunohistochemical assay, whereby positive expression of PDEFindicates that the patient is in need of therapeutic treatment for atype of cancer characterized by positive expression of PDEF. Thereafter,the patient is provided with the therapeutic treatment effective for thetype of cancer characterized by positive expression of PDEF. This methodcan be used to test tissue samples from breast tissue, prostate tissue,ovarian tissue, endometrial tissue, colon tissue, and cervical tissue,as they related to breast cancer, prostate cancer, ovarian cancer,endometrial cancer, colon cancer, and cervical cancer.

The present invention also relates to a method of treating or preventinga disease characterized by growth of tumor cells expressing PDEF. Thismethod involves administering to a subject a vaccine according to thepresent invention, thereby inducing T cell immunity that inhibits growthof tumor cells that express PDEF.

In another embodiment, the present invention relates to another methodof treating or preventing a disease characterized by growth of tumorcells expressing PDEF. The method involves administering to a subject avaccine according to the present invention, thereby inducing T cellimmunity that inhibits growth of tumor cells that express PDEF.

The present invention also relates to a method of treating or preventinga disease characterized by growth of tumor cells expressing PDEF, byadministering to a subject a small molecule inhibitor that inhibits PDEFexpression in tumors cell, thereby inhibiting growth of tumor cells thatexpress PDEF. A suitable small molecule inhibitor can include, forexample, an antisense oligonucleotide including at least 15 nucleotidesand having a nucleotide sequence that is complementary to at least 15nucleotides of an encoding nucleotide sequence of a PDEF fragment. ThePDEF fragment encoded by the nucleotide sequence can encode an aminoacid sequence selected from the group consisting of SEQ ID NO:2, SEQ IDNO:3, and SEQ ID NO:4; (ii) an amino acid sequence having at least 5continuous residues from SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4; or(iii) two or more amino acid sequences having at least 5 continuousresidues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.

In one aspect, the present invention relates to a method for detectingpre-existing spontaneous T cell response to human PDEF in a serum sampleof a subject. This method involves contacting the serum sample withpeptides corresponding to SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4under conditions such that an immunocomplex forms. The presence of theimmunocomplex is then detected, where such detection indicatespre-existing spontaneous T cell response to human PDEF in a serum sampleof the subject.

In another aspect, the present invention relates to a method fordetecting pre-existing spontaneous antibody response to human PDEF in asample of blood cells of a subject. This method involves contacting thesample of blood cells with overlapping peptides of at least 8 continuousresidues of the amino acid sequences corresponding to SEQ ID NO:2, SEQID NO:3, and/or SEQ ID NO:4. T cell proliferation by enzyme-linkedimmunospot (ELIspot) assay is then measured, where positive detectionindicates pre-existing spontaneous antibody response to human PDEF in asample of blood cells of a subject.

The present invention also relates to a method for boosting immunity ofa cancer patient to a cancer disease associated with positive expressionof PDEF. This method involves obtaining a tissue sample from the cancerpatient, where the tissue sample is suspected of including cancer tumortissue. The tissue sample is contacted with the antibody orantigen-binding fragment thereof according to the present invention,under conditions effective to allow for measuring the level of PDEFexpression in the tissue sample. The level of PDEF expressed in thetissue sample is measured using an immunohistochemical assay, wherebypositive expression of PDEF indicates that the patient is in need of anadditional immunization against PDEF. The patient is then tested for anypre-existing antibody or T cell response against PDEF, and finding ofsuch response makes patient a better candidate for receiving vaccinetreatment. The patient is then provided with a vaccine of the presentinvention under conditions effective to boost immunity of the cancerpatient to the cancer disease associated with positive expression ofPDEF. As contemplated by this method, the tissue sample can be selectedfrom the following tissues, without limitation: breast tissue, ovariantissue, endometrial tissue, colon tissue, and/or cervical tissue.Further, this method is effective in boosting the immunity of a cancerpatient to one of the following cancer diseases associated with positiveexpression of PDEF: breast cancer, ovarian cancer, endometrial cancer,colon cancer, and/or cervical cancer.

The scientific literature supports the view that PDEF (Prostate derivedEts transcription factor) is a significant player in breast, prostate,and ovarian cancer progression (1, 2). However, as noted previously inthe Background section, the lack of an anti-PDEF antibody thatspecifically binds to PDEF with high affinity has made it difficult todevelop prognostic, diagnostic, and treatments for cancers associatedwith positive expression of PDEF. The present invention and thesupporting Examples highlight the significance of an anti-PDEF antibodyin assessing PDEF expression levels in tissue samples from cancerpatients. Also, the importance and use of PDEF as a noveldiagnostic/prognostic marker and a therapeutic target against breast,prostate, and ovarian cancers is contemplated by the present invention.

Together, these results demonstrate an important role for PDEF in breastand prostate cancer progression, and support PDEF as a novel prognosticmarker in these cancers, as well as a target for developing specifictherapies against these cancers. In ovarian cancer, PDEF expressionassociates with the cancer phenotype, suggesting a diagnosticapplication for PDEF in this cancer. Based on these observations, it isexpected that, in the future, all newly diagnosed breast, prostate, andovarian tumors will be analyzed for PDEF expression, in order to predictsurvival and to select patients for receiving additional treatmentsincluding novel therapies targeted to PDEF.

The anti-PDEF antibody of the present invention represents the firstreagent useful for the evaluation of PDEF protein expression byimmunohistochemistry in primary tumors from patients. The presentinvention also contemplates the use of monoclonal antibodies against thePDEF-1-104 segment and/or against specific peptides derived from thissegment, or from other segments of PDEF, including PDEF-105-141 andPDEF-2,4-247, that show homology only to PDEF. Additionally, polyclonalor monoclonal antibodies against these PDEF peptides may be raised invarious species of mammals in addition to rabbit, e.g., in mice or goat.

The anti-PDEF antibody (or antigen-binding fragment thereof) can be usedto assay for PDEF expression levels in a number of prognostic anddiagnostic methods. For example, the antibody of the present inventioncan be used for prognostic stratification of breast cancer patients toidentify those at risk of early death.

The present invention further provides for the use of PDEF expressionlevels for prognostic stratification of patients, in particular, thosewith luminal breast tumors that comprise more than 80% of the newlydiagnosed breast cancers. The latter include ER+ tumors, Her2/neu+tumors, and apocrine breast tumors.

The present invention also provides for the use of PDEF expressionlevels to stratify luminal breast cancer patients with regard to thetherapeutic course of action, i.e., patients with high PDEF expressionmay be eligible to receive additional treatments, including thosetargeted to PDEF itself.

The present invention provides for prognostic stratification of patientswith prostate cancer based on the levels of PDEF expression in primaryprostate tumors, with regard to risk of early cancer recurrence.

The present invention also provides for the use of PDEF expressionlevels to stratify prostate cancer patients with regard to thetherapeutic course of action, i.e., patients with high PDEF expressionmay be eligible to receive additional treatments including thosetargeted to PDEF itself.

The present invention further provides for the use of PDEF antibody todiagnose ovarian cancer.

The present invention provides for prognostic stratification of patientswith ovarian cancer based on the levels of PDEF expression in primaryovarian tumors, with regard to risk of early cancer recurrence or poorsurvival.

The present invention also provides for the use of PDEF expressionlevels to stratify ovarian cancer patients with regard to thetherapeutic course of action, i.e., patients with high PDEF expressionmay be eligible to receive additional treatments including thosetargeted to PDEF itself.

The present invention further provides for use of PDEF antibody in otherdiseases in which changes in PDEF expression levels may dispose todisease development

The present invention provides for use of the PDEF-1-104 peptide fordeveloping novel therapeutics against breast, prostate, and ovariancancers, including small molecule inhibitors against this segment ofPDEF and vaccines derived from this segment of PDEF.

Additionally, the present invention provides for the use of PDEF-105-141peptide for developing novel therapeutic against breast, prostate, andovarian cancers, including small molecule inhibitors against thissegment of PDEF and vaccines derived from this segment of PDEF.

The present invention further provides for the use of PDEF-214-247peptide for developing novel therapeutic against breast, prostate, andovarian cancers, including small molecule inhibitors against thissegment of PDEF and vaccines derived from this segment of PDEF.

The present invention further provides for the use of PDEF-1-104,PDEF-105-141, and PDEF-214-247 peptides as probes to assess anypre-existing PDEF specific spontaneous immunity in breast and ovariancancer patients. This would allow selection of patients to receivePDEF-based vaccines to boost their immunity with a view to induce strongimmunity against breast and ovarian cancers.

The present invention is useful in overcoming the deficiencies in theprior art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a blast homology alignment search for human sequencesthat show significant homology to various segments of PDEF. Theseinclude: (i) N-terminal PDEF unique segment spanning amino acid residues1-104 (FIG. 1A); (ii) segment spanning amino acid residues 142-213corresponding to the Pointed domain (FIG. 1B); (iii) segment spanningamino acid residues 248-331 defining the DNA binding Ets domain (FIG.1C); (iv) PDEF unique segment spanning amino acid residues 105-141 (FIG.1D) and v) PDEF unique segment spanning amino acid residues 214-247(FIG. 1E).

FIG. 2 illustrates testing for the specificity of anti-PDEF antibodiesby Western blotting and immunohistochemistry. Panel A shows analysis ofPDEF protein expression in breast and non-breast tumor cell lines byWestern blotting. Equal amounts of total protein from breast tumor celllines MCF-7, SKBR3 and from non-breast tumor cell lines Hela and U937were run on 12% SDS PAGE and transferred to nitrocellulose membrane. Theupper-half of this panel shows the result of probing the blot withanti-PDEF antibodies and the lower-half shows a similar blot followingprobing with anti-actin antibody. The Panels B, C and D respectivelyshow specific nuclear staining of PDEF protein in the epithelial tumorcells from MCF-7 breast tumor cell line and in tissue section from aprimary breast carcinoma and a primary prostate carcinoma.

FIG. 3 illustrates additional testing of the specificity of anti-PDEFantibody by Western blotting. Upper panel shows reactivity with PDEFprotein from PDEF-transfected MCF-12A cells (left panel) and withrecombinant PDEF protein (right panel). No reactivity was observed withvector-transfected MCF-12A cells.

FIG. 4 illustrates additional testing of the specificity of anti-PDEFantibody by immunohistochemistry using normal human tissues. PDEFprotein expression was analyzed in a panel of normal human tissues.Photomicrographs show strong expression of PDEF in normal prostatetissue and the normal trachea/bronchus tissue (FIG. 4A). FIG. 4Bsummarizes the lack of reactivity of PDEF antibody in other normaltissues. This reactivity pattern was similar to that previously reportedfor PDEF mRNA expression in normal human tissues (3), and furthervalidates the specificity of this antibody.

FIG. 5 illustrates PDEF expression in matched pairs of benign breast andbreast tumor tissues from individual patients. The upper and lower pairsof photomicrographs show representative PDEF staining in matched samplesof adjacent benign breast versus breast tumor tissues from two patients.Increased staining in tumor tissues is seen in comparison to benigntissues. Results for PDEF staining in matched pairs from additional ninepatients are shown in Table 1. These results are also similar to thosepreviously reported for PDEF mRNA expression in matched samples ofadjacent benign and tumor tissues from breast cancer patients (3).Together, the results shown in FIGS. 4 and 5 show correspondence betweenPDEF mRNA and protein in normal human normal tissues and in human breasttumors, and rigorously demonstrate the specificity of the antibody ofthe present invention for PDEF by immunohistochemical assay.

FIGS. 6A-6D illustrate the characteristics of PDEF protein expression inprogression from benign breast tissue to carcinoma. PDEF expression inbenign breast tissues (FIG. 6A), intraductal carcinomas (DCIS) (FIG.6B), invasive ductal carcinomas (FIG. 6C) and invasive lobularcarcinomas (FIG. 6D) was examined using the antibody described herein.Negative samples (all tumor cells lacking staining) are identified usinga superscripted asterisk sign (*). The samples showing PDEF expressionbelow thresholds are identified using a superscripted triangle sign (▴).The superscripted plus signs (+) in the graphs represent individualsamples that stained above the selected thresholds and therefore scoredpositive for PDEF expression. The x-axis in these graphs shows differentlevels of staining intensity i.e. 1+, 2+ and 3+. The y-axis showspercent of positively staining cells in a given tumor sample.

FIGS. 7A-7C illustrate the characteristics of PDEF protein expression inprogression from benign prostate tissue to carcinoma. PDEF expression insamples from benign prostate tissues (FIG. 7A), prostate intraepithelialneoplasias (PIN) (FIG. 7B) and prostate carcinomas (FIG. 7C) wasexamined using the antibody described herein. Negative samples (alltumor cells lacking staining) are identified using a superscriptedasterisk sign (*). The samples showing PDEF expression below thresholdsare identified using a superscripted triangle sign (▴). Thesuperscripted plus signs (+) represent individual samples that stainedabove the selected thresholds and therefore scored positive for PDEFexpression. The x-axis in these graphs shows different levels ofstaining intensity i.e. 1+, 2+ and 3+. The y-axis shows percent ofpositively staining cells in a given tumor sample.

FIG. 8 illustrates the characteristics of PDEF expression in progressionfrom benign ovaries to carcinoma. PDEF expression in normal ovaries,cystademomas and in different types and stages of ovarian neoplasia wasexamined using the antibody described here. Panel 2A, negative stainingof normal ovary; Panel 2B, negative staining of cystadenoma; Panel 2C,positive PDEF expression in a low malignant potential tumor; Panel 2D,positive PDEF expression in stage I serous ovarian cancer and Panel 2E,positive PDEF expression in advanced stage serous ovarian cancer.

FIG. 9 illustrates enhanced tumorigenicity of PDEF expressing MCF-12 Acells. 10⁶ cells of PDEF-lacking (PDEF−) and PDEF-expressing (PDEF+)MCF-12A cells were injected s.c. into groups of 3 SCID mice each andtumor growth monitored. The tumor volume (mm3) at various time points isthe average for 3 mice from each group.

FIG. 10 illustrates a survival analysis with PDEF expression in patientswith ER-positive breast cancer. Six datasets with patient survival dataand PDEF expression data were studied. For each dataset, the low 25%quartile of PDEF expressing samples was categorized as low-expressionsamples; and the high 25% quartile as high-expression samples.Comparison of these low and high expression cohorts from the datasets(a) Chin et al. (9) and (b) Miller et al. (10) showed significantly pooroverall survival for the PDEF high expression cohort. Also, in thedataset (c) of Ivshina et al (11) that includes mixed clinical outcomedata on overall survival and metastases-free survival, a significantdifference was observed between low and high PDEF expression cohorts.The log-rank test p-values are also shown in the figure. In contrast, nosignificant difference was observed between low and high PDEF expressioncohorts with respect to relapse-free or metastases-free survival ofpatients in the datasets of (d) Wang et al. (12); (e) Minn et al. (13),and (f) Sotirious et al. (14).

FIG. 11 illustrates PDEF expression in different subtypes of breastcancer. These data were extracted from the gene expression profilingdata sets from Minn et al. (13) and Farmer et al. (15). As shown, PDEFwas not expressed in any of the 16 tumors of basal subtype. In contrast,20 of 27 (74%) of luminal tumors; 6 of 6 (100%) of apocrine tumors and21 of 23 (91%) Her2/neu-positive tumors expressed PDEF. A sample wasconsidered PDEF− positive if majority of the probe sets were scored“present” for PDEF. The error for the proportion is computed withassumption of binomial distribution.

FIG. 12 illustrates that high PDEF expression correlates withbiochemical PSA failure. PDEF staining score (0-316) was determined as aproduct of staining intensity and percentage of positively stained cellsin a sample. A cut off value of 180 staining score stratified patientsinto high and low PDEF categories.

FIG. 13A illustrates a representative experiment showing Pse specific Tcell immunity by ELISPOT assay for cytokine IFN-γ. Upper panels A, B andC respectively show representative images of individual wells showingIFN-γ secreting T cells/500,000 splenocytes from Pse-immunized (A);human Her2/neu-immunized (B) and vector-immunized (C) female mice. Thelower panels D, E and F, respectively, show data for similarly immunizedmale mice.

FIG. 13B illustrates quantitative Pse-specific T cell responses in FVBmice. Spleens were harvested from female and male mice followingimmunization (3 times at two-week interval) with Pse-DC, Her2/neu-DC orVector-DC respectively. Splenocytes were cultured for 5 days in thepresence of respective stimulators and IL-2. The number of Pse-specificIFN-γ secreting T cells was determined by ELIspot assay using Pse-DC,Her2/neu-DC and Vector-DC as target cells.

FIG. 14 illustrates quantitative Pse-specific T cell responses in C57BLmice. Spleens were harvested from female and male mice followingimmunization (3 times at two-week interval) with Pse-DC, Her2/neu-DC orVector-DC respectively. Splenocytes were cultured for 5 days in thepresence of respective stimulators and IL-2. The number of Pse-specificand IFN-γ secreting T cells was determined by ELIspot assay usingPse-DC, Her2/neu-DC and Vector-DC as target cells.

DETAILED DESCRIPTION OF THE INVENTION

Various abbreviations and terms are used throughout to describe variousaspects of the present invention. Below is a selected listing of certainof these abbreviations and terms.

As used herein, the abbreviation “PDEF” corresponds to Prostate derivedEts factor.

As used herein, the abbreviation “SPDEF” corresponds to Sam pointeddomain containing Ets factor.

As used herein, the abbreviation “ER” corresponds to Estrogen receptor.

As used herein, the abbreviation “Her2/neu” corresponds to humanepidermal growth factor receptor 2.

As used herein, the abbreviation “Ets” corresponds to erythrocytetransforming sequence, also known as E twenty-six (Ets) virustransforming sequence. This structural domain is present in 27 humanproteins belonging to the Ets family to which PDEF also belongs. The Etsdomain is used by these transcription factors to bind to DNA andregulate gene expression.

As used herein, the term “Pointed” corresponds to a structural motifpresent in proteins, primarily used in protein-protein interaction, inparticular, in homo or hetero di- and oligomerization.

As used herein, the abbreviation “MCF-7” corresponds to a human breasttumor cell line.

As used herein, the abbreviation “MCF-12A” corresponds to a lowmalignancy epithelial cell line derived from normal human breast.

As used herein, the abbreviation “s.c.” corresponds to Sub cutaneous.

As used herein, the abbreviation “pET15b” corresponds to a plasmidexpression vector for production of recombinant proteins in bacteria.

As used herein, the abbreviation “IPTG” corresponds to isopropylβ-D-1-thiogalactopyranoside.

As used herein, the abbreviation “PSA” corresponds to prostate specificantigen.

As used herein, the term “PDEF-1-104” corresponds to an N-terminalsegment of PDEF protein that includes amino acid residues 1 to 104 ofPDEF.

As used herein, the term “Gleason score” corresponds to a score given toprostate cancer based upon its microscopic appearance. Cancers with ahigher Gleason score are more aggressive and have a worse prognosis.

As used herein, the term “Biochemical PSA failure” refers to a surrogateendpoint for cancer recurrence and is defined as three consecutive risesof the PSA, before a failure is declared.

As used herein, the abbreviation “Pse-DC” corresponds to dendritic cellstransfected with Pse expression plasmid.

As used herein, the abbreviation term “Vector-DC” corresponds todendritic cells transfected with vector plasmid.

As used herein, the abbreviation “Her2/neu-DC” corresponds to dendriticcells transfected with Her2/neu expression plasmid.

As used herein, the abbreviation “IFN-γ” corresponds tointerferon-gamma.

As used herein, the abbreviation “IL-2” corresponds to interleukin-2

The present invention relates to anti-PDEF antibodies that specificallybind with high affinity to human PDEF. The anti-PDEF antibodies of thepresent invention have been confirmed to have high affinity to humanPDEF using immunohistochemical assays. The antibodies of the presentinvention have been shown to react with a protein that migrates at about46 kD in size, which is similar to the migration of recombinant PDEFprotein and of PDEF protein expressed by an MCF-12A cell line that wastransfected with PDEF expression plasmid (FIG. 2). Due to their highaffinity and their ability to be detected in immunohistochemical assays,the anti-PDEF antibodies of the present invention can be used, interalia, to evaluate PDEF expression by immunohistochemistry in the primarytumor samples from patients. The functionality of the anti-PDEFantibodies of the present invention makes these antibodies useful innumerous prognostic and diagnostic applications. Further, the anti-PDEFantibodies of the present invention can be used to assist in developingvaccines and other treatments of cancers that are associated withpositive expression of PDEF.

The uniqueness of the anti-PDEF antibodies of the present invention ascompared with previously reported anti-PDEF antibodies is readilyapparent, as noted below.

For example, as mentioned in the Background section hereof, antibodiesagainst specific peptides from PDEF are available from commercialsources. However, their use to evaluate PDEF expression byimmunohistochemistry in the primary tumor samples from patients has notbeen demonstrated. Notably, a PDEF antibody (termed PDEF (N-14):sc-46446), apparently raised against an N-terminal peptide, has beendescribed. (See Goat Anti-PDEF, N-14 polyclonal antibody, available fromSanta Cruz Biotechnology, Inc.). In Western blot assays, this antibodyreacts with a protein that migrates at 37 to 38 kD size. (Seewww.scbt.com/datasheet-46446-pdef-n-14-antibody.html). However, this isinconsistent with the migration patterns of recombinant PDEF protein andof PDEF protein expressed by MCF-12A cell line that was transfected withPDEF expression plasmid, both of which migrate at about 46 kD size. TheN-14 antibody is, therefore, different from the antibodies of thepresent invention. Additionally, the data specification sheet for theN-14 antibody states that it is not recommended for use in clinicaldiagnosis, which is in stark contrast to the anti-PDEF antibodies, whichare ideal for immunohistochemical assay based diagnostics.

Recently, another antibody to a large PDEF segment comprising amino acidresidues 1-250 was described. However, since this 1-250 residue segmentcontains the Pointed domain that is present in many other human Etsproteins (see FIG. 1B), use of this antibody is also likely to yieldnon-specific reactivity with other proteins in addition to PDEF.Consequently, its specificity for PDEF in immunohistochemical assay forstaining PDEF in tissue sections from a patient's tumors remains to bedemonstrated. A possible explanation for non-specific reactivity ofanti-PDEF antibodies in immunohistochemistry assays may be that duringantigen retrieval process, protein renaturation takes place, and thismay allow generation of new epitopes that are not present under thedenaturing conditions of Western blotting. This deficiency is not aproblem with the anti-PDEF antibodies of the present invention.

The uniqueness of the anti-PDEF antibodies of the present invention canalso be demonstrated by comparing it to another antibody purported to beraised against the 1-104 residues of PDEF. This particular polyclonalantibody was described by Ghadersohi et al. (6, 7). Unlike the anti-PDEFantibodies of the present invention, the specificity of the antibody ofGhadersohi et al. to PDEF was not demonstrated in an immunohistochemicalassay. In particular, Ghadersohi et al. were not able to use theirantibody to demonstrate correspondence between PDEF mRNA and proteinexpression in a panel of normal human tissues. Ghadersohi et al. werefurther unable to use their antibody to demonstrate increase inexpression of PDEF protein in the breast tumor tissue in comparison toadjacent benign breast tissue in matched samples from patients. To thecontrary, the antibody of Ghadersohi et al. showed strong reactivitywith normal breast and ovarian tissues (6, 7), and weak reactivity withtumors from these tissues.

The results with regard to the polyclonal antibody reported byGhadersohi et al. are contrary to the results obtained by the inventorwith regard to PDEF expression in breast and ovarian tissue (1, 2).Further, the anti-PDEF antibodies of the present invention have beenvalidated with regard to their specificity using a number of experimentsshown in FIGS. 2-5. By contrast, the antibody purportedly generated byGhadersohi et al. against residues 1-104 of PDEF does not appear to showspecificity for PDEF in the immunohistochemistry assay. Therefore, thereis compelling evidence to show that the anti-PDEF antibodies of thepresent invention are, indeed, distinguishable from any other purportedanti-PDEF antibody described in the art.

In one embodiment, the human PDEF that was used to generate thespecifically binding and high affinity anti-PDEF antibodies correspondedto the polypeptide product of a Homo sapiens SAM pointeddomain-containing ets transcription factor (referred to herein as“SPDEF”) having NCBI Accession No. NM_(—)012391 (incorporated byreference herein in its entirety). In particular, this PDEF has an aminoacid sequence of SEQ ID NO:1 is as follows:

(SEQ ID NO: 1) MGSASPGLSSVSPSHLLLPPDTVSRTGLEKAAAGAVGLERRDWSPSPPATPEQGLSAFYLSYFDMLYPEDSSWAAKAPGASSREEPPEEPEQCPVIDSQAPAGSLDLVPGGLTLEEHSLEQVQSMVVGEVLKDIETACKLLNITADPMDWSPSNVQKWLLWTEHQYRLPPMGKAFQELAGKELCAMSEEQFRQRSPLGGDVLHAHLDIWKSAAWMKERTSPGAIHYCASTSEESWTDSEVDSSCSGQPIHLWQFLKELLLKPHSYGRFIRWLNKEKGIFKIEDSAQVARLWGIRKNRPAMNYDKLSRSIRQYYKKGIIRKPDISQRLVYQFVHPI

The anti-PDEF antibody or antigen-binding fragment thereof of thepresent invention can be raised against a segment of the PDEF of SEQ IDNO:1 that is unique to PDEF, in that it does not have high homology withother non-PDEF Ets family members or any other polypeptides.

As provided herein, the present invention relates to various embodimentsof anti-PDEF antibodies (or antigen-binding fragments thereof) that areraised against the following amino acid segments of the PDEF of SEQ IDNO:1: (i) residues 1-104 of SEQ ID NO:1; (ii) residues 105-141 of SEQ IDNO:1; and/or (iii) residues 214-247 of SEQ ID NO:1.

Amino acid residues 1-104 of the human PDEF of SEQ ID NO:1 are describedbelow and correspond to SEQ ID NO:2, as follows:

(SEQ ID NO: 2) MGSASPGLSSVSPSHLLLPPDTVSRTGLEKAAAGAVGLERRDWSPSPPATPEQGLSAFYLSYFDMLYPEDSSWAAKAPGASSREEPPEEPEQCPVIDSQA PAGS

Amino acid residues 105-141 of the human PDEF of SEQ ID NO:1 aredescribed below and correspond to SEQ ID NO:3, as follows:

(SEQ ID NO: 3) LDLVPGGLTLEEHSLEQVQSMVVGEVLKDIETACKLL

Amino acid residues 214-247 of the human PDEF of SEQ ID NO:1 aredescribed below and correspond to SEQ ID NO:4, as follows:

(SEQ ID NO: 4) SAAWMKERTSPGAIHYCASTSEESWTDSEVDSSCSGQ

In one aspect, the present invention relates to an isolated antibody orantigen-binding fragment thereof that specifically binds with highaffinity to at least a portion of a segment of a human PDEF. Suitablesegments of PDEF can include, but are not limited to, the following: (a)amino acid residues 1-104 of SEQ ID NO:1; (b) amino acid residues105-141 of SEQ ID NO:1; (c) amino acid residues 214-247 of SEQ ID NO:1;or (d) the like.

In one embodiment, the antigen-binding fragment can include, forexample, an F(ab′)₂ fragment, an Fab′ fragment, an Fab fragment, or anFv fragment.

The antibody or antigen-binding fragment thereof of the presentinvention can be in the form of a polyclonal antibody, a monoclonalantibody, and/or a single chain antibody.

Monoclonal antibody production may be effected by techniques which arewell-known in the art. Basically, the process involves first obtainingimmune cells (lymphocytes) from the spleen of a mammal (e.g., mouse),which has been previously immunized with the antigen of interest eitherin vivo or in vitro. The antibody-secreting lymphocytes are then fusedwith (mouse) myeloma cells or transformed cells, which are capable ofreplicating indefinitely in cell culture, thereby producing an immortal,immunoglobulin-secreting cell line. The resulting fused cells, orhybridomas, are cultured, and the resulting colonies screened for theproduction of the desired monoclonal antibodies. Colonies producing suchantibodies are cloned, and grown either in vivo or in vitro to producelarge quantities of antibody. A description of the theoretical basis andpractical methodology of fusing such cells is set forth in Kohler andMilstein, Nature, 256:495 (1975), which is hereby incorporated byreference in its entirety.

As an example, mammalian lymphocytes are immunized by in vivoimmunization of the animal (e.g., a mouse) with the PDEF peptidefragment in accordance with the present invention. Such immunizationsare repeated as necessary at intervals of up to several weeks to obtaina sufficient titer of antibodies. Following the last antigen boost, theanimals are sacrificed and spleen cells removed.

Fusion with mammalian myeloma cells or other fusion partners capable ofreplicating indefinitely in cell culture is effected by standard andwell-known techniques, for example, by using polyethylene glycol (“PEG”)or other fusing agents. (See Milstein and Kohler, Eur. J. Immunol.,6:511 (1976), which is hereby incorporated by reference in itsentirety). This immortal cell line, which is preferably murine, but mayalso be derived from cells of other mammalian species, including but notlimited to rats and humans, is selected to be deficient in enzymesnecessary for the utilization of certain nutrients, to be capable ofrapid growth, and to have good fusion capability. Many such cell linesare known to those skilled in the art, and others are regularlydescribed. However, for the purpose of the present invention, it isimportant that the monoclonal antibodies specifically bind with highaffinity to PDEF so that they can be used in immunohistochemistry assaysaccording to the present invention.

Procedures for raising polyclonal antibodies are also well known.Typically, such antibodies can be raised by administering the subjectprotein or polypeptide (e.g., the PDEF fragments according to thepresent invention) subcutaneously to New Zealand white rabbits whichhave first been bled to obtain pre-immune serum. The antigens can beinjected at a total volume of 100 μl per site at six different sites.Each injected material will contain synthetic surfactant adjuvantpluronic polyols, or pulverized acrylamide gel containing the protein orpolypeptide after SDS-polyacrylamide gel electrophoresis. The rabbitsare then bled two weeks after the first injection and periodicallyboosted with the same antigen three times every six weeks. A sample ofserum is then collected 10 days after each boost. Polyclonal antibodiesare then recovered from the serum by affinity chromatography using thecorresponding antigen to capture the antibody. Ultimately, the rabbitsare euthanized (e.g., pentobarbital 150 mg/Kg IV). This and otherprocedures for raising polyclonal antibodies are disclosed in E. Harlow,et. al., editors, Antibodies: A Laboratory Manual (1988), which ishereby incorporated by reference in its entirety. However, for thepurpose of the present invention, it is important that the polyclonalantibodies specifically bind with high affinity to PDEF so that they canbe used in immunohistochemistry assays according to the presentinvention.

Polyclonal sera rendered monospecific for a particular target PDEFsegment may be made, for example, by preparing a PDEF polyclonalantiserum using the procedures described above, and then exposing thepolyclonal antiserum to hydroxyapatite beads coated with a non-targetpeptide fragment or non-target PDEF fragment, thereby removingantibodies cross-reactive to non-target peptide fragment or non-targetPDEF fragment. Monospecificity for a particular PDEF fragment can bedetermined by ELISA assay. Absorbance analyses can then be performed todetermine monospecificity for the target PDEF fragment. Serademonstrated to be monospecific can be employed in the assays of thepresent invention, as one embodiment.

As indicated above, biological agents suitable for use in accordancewith the present invention include antibodies, such as monoclonal orpolyclonal antibodies. In addition, antibody fragments (antigen bindingportions), half-antibodies, hybrid derivatives, probes, and othermolecular constructs that are specific for a particular PDEF fragmentmay also be utilized.

As mentioned previously, exemplary antibody fragments include, withoutlimitation, Fab fragments, Fab′ fragments, F(ab)₂, fragments, F(ab′)₂fragments, Fd fragments, Fv fragments, dAb fragments, and isolatedcomplementarity determining regions (“CDRs”) (see U.S. Pat. Nos.7,037,498, 7,034,121, 7,041,870, and 7,074,405, which are herebyincorporated by reference in their entirety). These antibody fragmentscan be made by conventional procedures, such as proteolyticfragmentation procedures, as described in J. Goding, MonoclonalAntibodies: Principles and Practice, pp. 98-118 (N.Y. Academic Press1983), which is hereby incorporated by reference in its entirety.

In addition, the antibody or antigen-binding fragment thereof can bedetectably labeled. Suitable detectable labels for use with the antibody(or antigen-binding fragment thereof) of the present invention caninclude, without limitation, a radioisotope, an affinity label, anenzymatic label, a fluorescent label, and a paramagnetic atom.

As indicated above, detection of PDEF may also be accomplished using anyof a variety of other immunoassays in conjunction with the anti-PDEFantibodies of the present invention. For example, by radioactivelylabeling the antibody or antibody fragment or probe of the presentinvention, it is possible to detect the PDEF protein that the antibodyor antibody fragment or probe was designed for through the use of aradioimmunoassay (RIA) (see, e.g., Weintraub, Principles ofRadioimmunoassays, Seventh Training Course on Radioligand AssayTechniques, The Endocrine Society (1986), which is hereby incorporatedby reference in its entirety). The radioactive isotope can be detectedby such means as the use of a gamma counter or a scintillation counteror by autoradiography.

It is also possible to label the antibody or antibody fragment or probeof the present invention with a fluorescent compound. When thefluorescently labeled antibody or antibody fragment or probe is exposedto light of the proper wavelength, its presence can then be detected dueto fluorescence. Among the most commonly used fluorescent labelingcompounds are fluorescein isothiocyanate, rhodamine, phycoerythrin,phycocyanin, allophycocyanin, o-phthaldehyde and fluorescamine, butothers known in the art are contemplated by the present invention.

The antibody or antibody fragment or probe of the present invention canalso be detectably labeled using fluorescence emitting metals such as¹⁵²Eu, or others of the lanthanide series. These metals can be attachedto the antibody or antibody fragment or probe of the present inventionusing such metal chelating groups as diethylenetriaminepentacetic acid(DTPA) or ethylenediaminetetraacetic acid (EDTA).

The antibody or antibody fragment or probe of the present invention canalso be detectably labeled by coupling it to a chemiluminescentcompound. The presence of the chemiluminescent-tagged antibody orantibody fragment or probe is then determined by detecting the presenceof luminescence that arises during the course of a chemical reaction.Examples of particularly useful chemiluminescent labeling compounds areluminol, isoluminol, theromatic acridinium ester, imidazole, acridiniumsalt, and oxalate ester.

Likewise, a bioluminescent compound may be used to label the antibody orantibody fragment or probe of the present invention. Bioluminescence isa type of chemiluminescence found in biological systems, in which acatalytic protein increases the efficiency of the chemiluminescentreaction. The presence of a bioluminescent protein is determined bydetecting the presence of luminescence. Important bioluminescentcompounds for purposes of labeling are luciferin, luciferase andaequorin.

In order to validate the specificity and binding affinity of anyantibodies or antigen-binding fragments thereof to PDEF, it is importantto conduct immunohistochemical assays using the antibodies(antigen-binding fragments). As noted previously, unlike previouslyreported anti-PDEF antibodies in the art, the antibody orantigen-binding fragment thereof of the present invention has been shownto bind specifically and with high affinity to PDEF usingimmunohistochemical assays. Therefore, a suitable antibody orantigen-binding fragment thereof of the present invention is one that ischaracterized as exhibiting: (a) strong staining intensity as determinedin an immunohistochemical assay with three or less of the normal tissuesbeing selected from the group consisting of prostate gland tissue,salivary gland tissue, and trachea/bronchus tissue; and (b) negativestaining intensity as determined by an immunohistochemical assay withthree or more tissues selected from the group consisting of adrenalgland tissue, blood, brain tissue, bone marrow, heart tissue, livertissue, lung tissue, lymph node tissue, kidney tissue, ovary tissue,placenta tissue, spleen tissue, skeletal muscle tissue, thymus tissue,and testis tissue.

In accordance with the present invention, particularly regarding theimmunohistochemical assay aspect thereof, PDEF-negative tissue orsamples can include, without limitation, adrenal gland tissue, blood,brain tissue, bone marrow tissue, heart tissue, liver tissue, lungtissue, lymph node tissue, kidney tissue, ovary tissue, placenta tissue,spleen tissue, skeletal muscle tissue, thymus tissue, and testis tissue.

In accordance with the present invention, particularly regarding theimmunohistochemical assay aspect thereof, criteria for positiveexpression for PDEF can include, without limitation: (i) a minimum of30% tumor cells staining at 1+ intensity; (ii) a minimum of 15% tumorcells staining at 2+ intensity; or (iii) a minimum of 10% tumor cellsstaining at 3+ intensity. Similar criteria can also be applied fornormal tissues. Criteria for “negative” expression for PDEF can include,without limitation, any tissue that contains less than 5% cells stainingpositive for PDEF. “Strong” expression is defined herein as a minimum of30% of cells stained at 3+ intensity.

To generate more specific PDEF antibodies, a comparison of the sequenceof PDEF with other members of the Ets factor family was conducted, whichshowed that a large segment at the N-terminus of the PDEF protein,spanning amino acid residues 1-140 (PDEF-1-140), showed homology only toPDEF, and not to any other human protein. This PDEF segment wastherefore produced as recombinant protein in bacteria and then used toimmunize rabbits to produce polyclonal antibodies, as discussed in moredetail in the Examples.

As with previously described antibodies to full-length PDEF, theantibodies to PDEF-1-104 peptide reacted specifically with PDEF proteinby Western blot assay. However, since application of an antibody inclinical diagnosis requires the use of immunohistochemistry assay, itwas necessary to demonstrate the specificity of the antibody in theimmunohistochemistry assay. For this purpose, an assay was developedthat included testing the reactivity of the antibody of the presentinvention in a panel of normal human tissues (A6). These included: (i)normal prostate and trachea/bronchus tissues that were previously shownto express PDEF and (ii) a number of other normal tissues such as brain,heart, kidney, liver, lung, skeletal muscle, spleen, testis that did notexpress PDEF mRNA (A1-3). When this assay was done, the PDEF-1-104antibody showed a reactivity pattern similar to that described for PDEFmRNA expression, and this validated the specificity of the PDEF-1-104antibody for PDEF in the immunohistochemical assay, to evaluate PDEFexpression in a patient's samples.

Previous work had shown frequent over expression of PDEF mRNA in humanbreast and ovarian tumors (3, 21); however, due to lack of suitableantibodies, PDEF protein expression could not be evaluated.Consequently, a direct role for PDEF in tumor progression could not beproposed or ascertained. Meanwhile, other labs using a small number ofpatient samples reported the loss of PDEF protein expression inprogression from benign breast and prostate tissues to carcinomas (4,5), suggesting an apparent loss of PDEF protein in the tumor tissue.However, these studies used antibodies to full-length PDEF proteins thatwere demonstrated to give uncharacteristic reactivity with normaltissues, presumably due to cross reaction of those antibodies with thehomologous Ets and Pointed domains present in other Ets proteins. Thisproblem is particularly acute since many of the non-PDEF Ets factors areexpressed at much higher levels than PDEF in the normal mammary glandand in mammary tumor tissues (22, 23).

In contrast, the present invention relates to a well-characterizedantibody that was used to analyze a large number of patients' samples.Therefore, the anti-PDEF antibody of the present invention was used todemonstrate the first showing of over expression of the PDEF protein inprogression from benign breast, prostate, and ovarian tissues tocarcinomas, supporting an important role for PDEF in the progression ofthese cancers.

In a particular embodiment, the isolated antibody or antigen-bindingfragment thereof of the present invention is an anti-PDEF polyclonalantibody that is effective for use in prognosis and diagnosis of PDEF intissue, blood, or other samples. The specificity and high affinity ofthis anti-PDEF antibody to PDEF has been validated usingimmunohistochemical assays, as further described in the Examplesdescribed herein. This isolated anti-PDEF antibody has been depositedfor storage and dissemination at the inventor's laboratory, located atthe Department of Immunology, Roswell Park Cancer Institute, Elm andCarlton Streets, Buffalo, N.Y. 14263.

In another aspect, the present invention relates to a hybridoma thatproduces the antibody according to the present invention, particularlyan antibody of the present invention where the antibody is a monoclonalantibody.

In yet another aspect, the present invention relates to a diagnostickit. This kit can include, without limitation, (a) a first containercontaining the antibody or antigen-binding fragment thereof, asmentioned herein; and (b) a second container for detection of theantibody or antigen-binding fragment thereof, wherein the secondcontainer comprises a label. The diagnostic kit of the present inventioncan further include at least one third container selected from the groupconsisting of a wash reagent and a detection reagent.

Because the present invention provides, for the first time, an anti-PDEFantibody that specifically binds to PDEF with high affinity, and becauseof the importance of PDEF in the progression of certain types of cancer,the present invention now makes it possible to use PDEF as a biomarkerfor prognostic and diagnostic methods for such cancers. The use of PDEFas a biomarker for certain of these particular cancers is describedbelow.

It should be pointed out that evaluating the expression of a putativecancer biomarker by immunohistochemistry is critical since this methodis primarily used in clinical diagnosis. Specifically,immunohistochemistry provides a much more detailed picture of thecharacteristic of a biomarker expression in the tumor and itsmicroenvironment, i.e., (i) whether the expression is restricted toepithelial tumor cells; (ii) whether increased expression is due toincreased number of tumor cells or due to high level staining by a smallfraction of cells; and or both; and (iii) whether other cells in thetumor microenvironment including inflammatory leukocytes, endothelialcells, and/or stromal cells express the specific biomarker.

In contrast, methods such as Western blotting do not provide suchdetail. Consequently, immunohistochemistry is the primary assay used forevaluating the expression of prognostic, predictive, and therapeutictumor markers. Unlike other apparent anti-PDEF antibodies described inthe art, the anti-PDEF antibody of the present invention has been shownto be effective in immunohistochemistry assays.

As examples of immunohistochemistry assays used in tandem with otherbiomarkers in the art (i.e., other than the PDEF biomarker), expressionof the ER and Her2/neu in breast cancer and of androgen receptor (AR) inprostate cancer is primarily done by immunohistochemistry assays.Therefore, it becomes necessary to demonstrate the specificity of anantibody to novel cancer biomarkers in an immunohistochemical assay.

As indicated previously, despite recent gains, primarily stemming fromthe use of mammography for early detection of breast cancer and the PSAtest for prostate cancer, mortality rates from advanced stage andmetastatic disease remain unchanged. Novel biomarkers of clinicalsignificance are needed to more accurately predict the course of thedisease and to serve as targets for developing novel therapeutics tominimize mortality from breast, prostate and ovarian cancers.

For example, estrogen receptor and Her2/neu are the two currently knownbiomarkers of clinical significance that predict the course of diseaseand serve as targets against which specific inhibitors and/or antibodieshave shown considerable clinical benefits to breast cancer patients.However, many patients develop resistance to these single agent-targetedtreatment approaches and continue to suffer from disease recurrence andprogression. Novel biomarkers of clinical significance are needed tominimize disease recurrence and progression in breast cancer patients.To that end, PDEF appears to be a highly promising novelprognostic/predictive marker and a target against breast cancer.Moreover, it is frequently expressed in ER+, Her2/neu-positive, andapocrine breast tumors of luminal origin (FIG. 11) that, together,comprise more than 80% of the newly diagnosed breast cancers.Simultaneous targeting of ER or Her2/neu with PDEF could provide animportant novel approach to control of disease progression in a largepopulation of breast cancer patients.

In prostate cancer, periodic monitoring of PSA levels is used to followdisease recurrence; and three consecutive increases in PSA levels is asurrogate marker of disease recurrence. However, in many cases, this istoo late to offer effective additional treatments to patients, so theability to predict the risk of disease recurrence early is important tohave a better chance at effective treatments. To that end, high PDEFexpression levels in primary tumors should allow early identification ofthe patients at high risk for cancer recurrence and those patients couldreceive additional treatments including those targeted to PDEF itself.Another study previously suggested a role for PDEF in prostate cancerprogression based on the ability of PDEF to induce PSA expression in aprostate tumor cell line (19). Since then, those same authors havepublished work that contradicts their earlier proposal (20).Investigations regarding the present invention represent the firstreport to provide direct evidence for a role for PDEF in prostate tumorprogression, based on the correlation with higher Gleason score andearly Biochemical PSA failure. Again, this was possible because of thehigh specificity of the anti-PDEF antibody of the present invention toPDEF and the usefulness and effectiveness of this antibody in animmunohistochemistry assay.

In ovarian cancer, PDEF is not expressed in normal ovaries or in benigncystadenomas that are considered as precursors to cancer. Consequently,PDEF may serve as a diagnostic marker of cancer in ovarian cancer.Further, since PDEF is a transcription factor, some of the downstreamtarget genes induced by PDEF could encode secreted or shed proteins thatmay appear in the serum, and serve as markers for early detection ofovarian cancer. Additionally, like breast and prostate cancer, PDEFcould serve as a target for developing novel therapies against ovariancancer.

It should be noted that two other studies, using PDEF mRNA quantitation,did not reveal any significant differences in the survival of patients(16) or revealed a correlation between lack of PDEF expression and poorsurvival of breast cancer patients (6). However, in these studies, basalsubtype of breast tumors that are quite aggressive, constitute about 15%of breast tumors and naturally lack PDEF expression were not excludedfrom analyses. This could have masked the effect of high PDEF expressionin luminal breast tumors present in the analysis cohorts. The basalsubtype of breast tumors are a biologically distinct entity carrying aunique gene expression signature that is different from other breastcancer subtypes including ER+, Her2/neu+ and AR+ breast cancer subtypes,each with distinct propensity for progression (17). Therefore, it iscritical to evaluate the prognostic utility of a given biomarkers withinthe same breast cancer subtype.

Accordingly, in the analysis relating to the present invention shown inFIG. 10, only ER+ luminal subtype breast tumors that constitute about ⅔rd of newly diagnosed breast cancer were analyzed, and as shown, inthree independent datasets high PDEF levels in tumors showed significantcorrelation with poor overall survival of patients. Data in FIG. 10showed no correlation between high PDEF expression and tumor relapse andmetastases. Presumably, PDEF as a transcription factor alters theexpression of genes to enhance anchorage independent tumor cell survivaland decrease tumor cell apoptosis (18) and not genes that promote tumorrecurrence, invasion and metastasis.

As noted, another novel finding due to the present invention is thecorrelation of high PDEF expression with poor overall survival of breastcancer patients, in particular, for luminal lineage derived tumors, asdemonstrated for the ER+ breast tumors in FIG. 10. This correlation doesnot apply to tumors arising from the basal cell lineage that compriseabout 15% of the newly diagnosed breast cancer. These tumors inherentlydo not express PDEF and their aggressive behavior may be attributable totheir mesenchymal like phenotype, which renders tumors more motile andinvasive.

Due to its specificity to PDEF and its applicability toimmunohistochemical assays, the anti-PDEF antibody of the presentinvention can be used in detecting the PDEF biomarker with regard to allof the cancers described above, as well as any other cancers associatedwith positive expression of PDEF.

In accordance with the present invention, vaccines can be derived fromthe PDEF-unique peptides of SEQ ID NO:2, SEQ ID NO:3; and SEQ ID NO:4.For example, suitable types of vaccines can include, without limitation,(i) DNA or RNA viral vectors incorporating the encoded peptidesequences; (ii) plasmid vectors using cytomegalo virus promoter and theencoded PDEF-unique peptides; (iii) plasmid vectors used in conjunctionwith electroporation to enhance their expression; (iv) overlappingpeptides of 8 to 15 amino acids long as peptide vaccines in conjunctionwith an adjuvant; and (v) nanoparticles including 8-15 amino acid longpeptides emulsified with an adjuvant.

Various pharmacologically acceptable carriers or adjuvants well known inthe art can be used with the vaccines of the present invention.

In one aspect, the present invention relates to a vaccine for immunizingan individual against a cancer disease associated with positiveexpression of PDEF. As used herein, a cancer disease associated withpositive expression of PDEF includes, without limitation, breast cancer,prostate cancer, ovarian cancer, endometrial cancer, colon cancer, andcervical cancer. The vaccine includes a polypeptide corresponding to aPDEF fragment that is effective to induce an immune response to PDEF inthe individual. Suitable PDEF fragments can include, for example, a PDEFfragment having (i) an amino acid sequence corresponding to SEQ ID NO:2,SEQ ID NO:3, and/or SEQ ID NO:4; (ii) an amino acid sequence having atleast 8 continuous residues from SEQ ID NO:2, SEQ ID NO:3, or SEQ IDNO:4; or (iii) two or more amino acid sequences having at least 8continuous residues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.In addition to the PDEF fragment, the vaccine of the present inventioncan included a pharmacologically acceptable carrier or adjuvant.

In one embodiment, the vaccine can further include a nanoparticlevaccine having a peptide of at least 8 continuous residues from SEQ IDNO:2, SEQ ID NO:3, and/or SEQ ID NO:4.

In still another aspect, the present invention relates to a method forimmunizing an individual against a cancer disease associated withpositive PDEF expression. This method involves administering the vaccineof the present invention into the individual. Suitable individuals forPDEF immunization can include, without limitation, a individual that ishigh risk for, predisposed to, susceptible to, and/or diagnosed withsaid cancer disease associated with positive PDEF expression. The methodis effective to immunize against such diseases that include, but are notlimited to, breast cancer, prostate cancer, ovarian cancer, endometrialcancer, colon cancer, and/or cervical cancer.

In a further aspect, the present invention relates to a viral or plasmidexpression vector. This viral or plasmid expression vector includes anucleotide sequence that is operably linked to a promoter and thatencodes an antigen. Suitable antigens can include, without limitation, aPDEF fragment having the following: (i) an amino acid sequencecorresponding to SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4; (ii) anamino acid sequence having at least 8 continuous residues from SEQ IDNO:2, SEQ ID NO:3, or SEQ ID NO:4; or (iii) two or more amino acidsequences having at least 8 continuous residues from SEQ ID NO:2, SEQ IDNO:3, and/or SEQ ID NO:4.

The present invention also relates to a vaccine having (a) theexpression vector of the present invention discussed herein and (b) apharmacologically acceptable carrier or adjuvant.

The present invention further relates to a method for immunizing anindividual against a cancer disease associated with positive PDEFexpression by administering the vaccine of the present invention to theindividual, where the individual is at high risk for, predisposed to,susceptible to, and/or diagnosed with the cancer disease associated withpositive PDEF expression. The method is effective to immunize againstsuch diseases that include, but are not limited to, breast cancer,prostate cancer, ovarian cancer, endometrial cancer, colon cancer,and/or cervical cancer.

PDEF is over expressed early in in situ breast carcinomas. Therefore,PDEF-based therapeutics can also be applied to primary prevention ofbreast cancer. Prophylactic vaccination is of special interest to olderwomen over age 65, since the incidence of breast cancer in this agegroup is more than 6-fold higher than in younger women, and about 50% ofthe newly diagnosed breast cancers occur in this age group. There are anestimated 29 million women over age 65 in the United States alone whoare at high risk for developing breast cancer, and they would benefitfrom preventive approaches targeted to PDEF. This suggests the potentialfor high impact of the present invention on the primary prevention ofbreast cancer.

In another aspect, the present invention relates to a method ofpreparing a polyclonal antibody that specifically binds with highaffinity to PDEF. This method involves immunizing an animal with a PDEFfragment having an amino acid sequence corresponding to SEQ ID NO:2, SEQID NO:3, and/or SEQ ID NO:4 under conditions effective to elicit anantibody response. The antibodies are isolated from the animal.Thereafter, this method involves screening the isolated antibodies usingan immunohistochemical assay to identify a polyclonal antibody thatspecifically binds with high affinity to PDEF. The polyclonal antibodyif then isolated. The present invention also relates to a polyclonalantibody produced by this method.

In still another aspect, this invention relates to a method forgenerating a monoclonal antibody that specifically binds with highaffinity to PDEF. This method involves administering to an animal anamount of an immunogenic composition that includes a PDEF segmenteffective to stimulate a detectable immune response. A suitable PDEFsegment can include, without limitation, an amino acid sequencecorresponding SEQ ID NO:2, SEQ ID NO:3, and SEQ ID NO:4. Thereafter,antibody-producing cells are obtained from the animal and theantibody-producing cells are fused with myeloma cells to obtainantibody-producing hybridomas. A hybridoma is selected that produces amonoclonal antibody that specifically binds with high affinity to PDEF,where the high affinity is confirmed using an immunohistochemical assay.Thereafter, the selected hybridoma is cultured in a cell culture thatproduces the monoclonal antibody. The monoclonal antibody is thenobtained from the cell culture.

The present invention also relates to a method of determining whether ahuman subject is susceptible to a type of cancer characterized bypositive expression of PDEF. This method involves obtaining a tissuesample from a subject, where the tissue sample is suspected of being acancer tumor tissue. The tissue sample is then contacted with theantibody or antigen-binding fragment thereof according to the presentinvention, and under conditions effective to allow for measuring thelevel of PDEF expression in the tissue sample. Under this method,measuring the level of PDEF expressed in the tissue sample using animmunohistochemical assay, whereby positive expression of PDEF indicatesthat the subject is susceptible to a type of cancer characterized bypositive expression of PDEF.

Suitable tissue samples can include breast tissue, prostate tissue,ovarian tissue, endometrial tissue, colon tissue, and cervical tissue.This method can be used with regard to breast cancer, prostate cancer,ovarian cancer, endometrial cancer, colon cancer, and cervical cancer.

In another aspect, the present invention relates to a method ofprognostic stratification of a cancer patient for targeted therapeuticcancer treatment. This method involves obtaining a tissue sample fromthe cancer patient, where the tissue sample is suspected of includingcancer tumor tissue. The tissue sample is contacted with the antibody orantigen-binding fragment thereof of the present invention so as to beeffective to allow for measuring the level of PDEF expression in thetissue sample. The level of PDEF is then measured in the tissue sampleusing an immunohistochemical assay, whereby positive expression of PDEFindicates that the patient is in need of therapeutic treatment for atype of cancer characterized by positive expression of PDEF. Thereafter,the patient is provided with the therapeutic treatment effective for thetype of cancer characterized by positive expression of PDEF. This methodcan be used to test tissue samples from breast tissue, prostate tissue,ovarian tissue, endometrial tissue, colon tissue, and cervical tissue,as they related to breast cancer, prostate cancer, ovarian cancer,endometrial cancer, colon cancer, and cervical cancer.

Additionally, in recent years “prognostic gene signatures” have beenidentified that predict clinical outcome for breast cancer patients(24). Two of these gene signatures, including Oncotype DX (25) andMammaPrint (26), appear robust and are presently being marketed forprognostic evaluation in breast cancer. An important limitation of thegene expression signatures is that their roles in determining prognosisis not completely understood, i.e., what tumor characteristics (e.g.tumor growth, invasiveness, metastasis, and/or survival) are beingaffected by specific genes in the signature.

Consequently, these aforementioned prognostic gene signatures do notoffer the opportunity to develop novel therapeutics targeted toindividual genes in the signature. In contrast, individual biomarkers,when validated, allow the development of highly specific targetedtherapeutics with minimal side effects. In this regard, ER and Her2/neuin breast cancer and androgen receptor (AR) in prostate cancer are notonly prognostic/predictive biomarkers, but they also serve as usefultargets of specific novel treatment approaches, i.e., tamoxifen andaromatase inhibitors that inhibit ER function; Herceptin that inhibitsHer2/neu function, and androgen antagonists that inhibit AR function.Similar to these biomarkers, PDEF is expected to be a usefulprognostic/predictive marker and a novel target for developing specificdrugs or vaccines against breast, prostate, and ovarian cancers, andsuch specific targeting of cancer is expected to show minimal sideeffects.

An example of steps involved in the use of anti-PDEF antibody fordetermining prognosis and for stratification of a breast cancer patientfor treatment selection, is as follows:

Step 1: A breast cancer patient arrives in the clinic, undergoes surgeryto remove cancer.

Step 2: A pathologist prepares the tumor sample for standardimmunohistochemistry for evaluating ER and Her2/neu expression. If thetumor is ER+, the tumor will be further screened with anti-PDEF antibodyto determine PDEF status.

Step 3: If the tumor is ER+PDEF−, i.e., stains positive for ER andnegative for PDEF, the patient's prognosis is good and patients willreceive Tamoxifen treatment. If, on the other hand, the tumor isER+PDEF+, i.e., stains positive for both ER and PDEF, the prognosis isbad and patient will receive Tamoxifen and a new drug or vaccinetargeted to PDEF.

The above example is restricted only to ER+ tumors, but it iscontemplated by the present invention that such a method can be used forHer2/neu+ luminal breast tumors, where high expression of PDEF will alsopredict poor prognosis and similarly allow stratification of patients toreceive either Herceptin alone or Herceptin and a PDEF-targeted drug orvaccine in case of low PDEF and high PDEF, respectively. These stepsalso apply to patients with AR+ breast tumors in which PDEF is expressedin all tumors.

Similar considerations will apply for ovarian cancer patients and forprostate cancer patients, except that PDEF-based vaccines may not beuseful for prostate cancer patients, since data generated with mice showthat males respond poorly to Pse (prostate specific Ets, mouse homologueof PDEF) vaccine, perhaps due to tolerance to Pse as a self antigenbecause of its strong expression in normal prostate. For prostate cancerpatients, small molecule inhibitor based drugs will be useful.

The present invention also relates to a method of treating or preventinga disease characterized by growth of tumor cells expressing PDEF. Thismethod involves administering to a subject a vaccine according to thepresent invention, thereby inducing T cell immunity that inhibits growthof tumor cells that express PDEF.

The present invention also relates to a method of treating or preventinga disease characterized by growth of tumor cells expressing PDEF, byadministering to a subject a small molecule inhibitor that inhibits PDEFexpression in tumors cell, thereby inhibiting growth of tumor cells thatexpress PDEF. A suitable small molecule inhibitor can include, forexample, an antisense oligonucleotide including at least 15 nucleotidesand having a nucleotide sequence that is complementary to at least 15nucleotides of an encoding nucleotide sequence of a PDEF fragment. ThePDEF fragment encoded by the nucleotide sequence can encode an aminoacid sequence selected from the group consisting of SEQ ID NO:2, SEQ IDNO:3, and SEQ ID NO:4; (ii) an amino acid sequence having at least 5continuous residues from SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4; or(iii) two or more amino acid sequences having at least 5 continuousresidues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.

In one aspect, the present invention relates to a method for detectingpre-existing spontaneous antibody response to human PDEF in a serumsample of a subject. This method involves contacting the serum samplewith peptides corresponding to SEQ ID NO:2, SEQ ID NO:3, and/or SEQ IDNO:4 under conditions such that an immunocomplex forms. The presence ofthe immunocomplex is then detected, where such detection indicatespre-existing spontaneous T cell response to human PDEF in a serum sampleof the subject.

In another aspect, the present invention relates to a method fordetecting pre-existing spontaneous T cell response to human PDEF in asample of blood cells of a subject. This method involves contacting thesample of blood cells with overlapping peptides of at least 8 continuousresidues of the amino acid sequences corresponding to SEQ ID NO:2, SEQID NO:3, and/or SEQ ID NO:4. T cell proliferation by enzyme-linkedimmunospot (ELIspot) assay is then measured, where positive detectionindicates pre-existing spontaneous antibody response to human PDEF in asample of blood cells of a subject.

The present invention also relates to a method for boosting immunity ofa cancer patient to a cancer disease associated with positive expressionof PDEF. This method involves obtaining a tissue sample from the cancerpatient, where the tissue sample is suspected of including cancer tumortissue. The tissue sample is contacted with the antibody orantigen-binding fragment thereof according to the present invention,under conditions effective to allow for measuring the level of PDEFexpression in the tissue sample. The level of PDEF expressed in thetissue sample is measured using an immunohistochemical assay, wherebypositive expression of PDEF indicates that the patient is in need of anadditional immunization against PDEF. The patient is then tested for anypre-existing antibody or T cell response against PDEF, and finding ofsuch response makes patient a better candidate for receiving vaccinetreatment. The patient is then provided with a vaccine of the presentinvention under conditions effective to boost immunity of the cancerpatient to the cancer disease associated with positive expression ofPDEF. As contemplated by this method, the tissue sample can be selectedfrom the following tissues, without limitation: breast tissue, ovariantissue, endometrial tissue, colon tissue, and/or cervical tissue.Further, this method is effective in boosting the immunity of a cancerpatient to one of the following cancer diseases associated with positiveexpression of PDEF: breast cancer, ovarian cancer, endometrial cancer,colon cancer, and/or cervical cancer.

The present invention is illustrated by the following examples.

EXAMPLES

The following examples are intended to illustrate particular embodimentsof the present invention, but are by no means intended to limit thescope of the present invention.

Certain of the Examples presented herein below include experimental dataperformed by the inventor and published in the following articles: (i)Sood, A. K., Saxena, R., Groth, J. et al., “Expression Characteristicsof PDEF Support a Role in Breast and Prostate Cancer Progression,” Hum.Pathol. 38(11):1628-1638 (2007) and (ii) Rodabaugh, M. D., et al.,“Prostate Derived Ets Factor is Overexpressed in Serous EpithelialOvarian Tumors,” Int. J. Gynecol. Pathol. 26(1):10-15 (2007), the entiredisclosures of which are hereby incorporated by reference in theirentirety.

Example 1 Antibody Production: Anti-PDEF Antibody

A Blast homology search for PDEF protein sequence showed significanthomology (60-74% amino acid residue homology, as shown in FIG. 1C) withthe C-terminal DNA binding Ets domain of PDEF with that of other Etsfactors. Also, there is significant homology in the Pointed domain ofPDEF with other human Ets factor proteins (shown in FIG. 1B). Incontrast, the N-terminal segment of PDEF comprising residues 1 to 104(PDEF-1-104) revealed homology only to PDEF (shown in FIG. 1A).Therefore, this PDEF-1-104 segment was selected for producing polyclonalantibodies in rabbits. Briefly, the cDNA encoding the N-terminal 1 to104 amino acids was PCR-amplified and subcloned into the bacterialexpression vector pET15b (Novagen, Madison, Wis.) at the Nde I site.After confirmation of the orientation and sequence, E. coli BL21 (DE3)cells were transformed by the resultant pET15b-PDEF-1-104 plasmid. Thecells were induced by 1 mM IPTG and PDEF protein was purified frombacterial lysates by affinity chromatography on a Ni-NTA column. Furtherpurification on MonoQ column (Amersham, Piscataway, N.J.) provided purepreparations of the PDEF-1-104 peptide. The purified PDEF-1-104 peptidewas used for production of polyclonal antibodies in rabbits. Briefly,two New Zealand white rabbits each were immunized by intradermalinjection of 100 μg of PDEF-1-104 protein emulsified in completeFreund's adjuvant. This was followed by three booster injections with150 μg protein in incomplete Freund's adjuvant at two-week interval andthe 4^(th) injection at 6 weeks following the third boost. Serum wascollected and tested for reactivity by ELISA and Western blot assaysusing purified PDEF protein as an antigen. PDEF antibodies were furtherpurified on a PDEF-full-length protein-immobilized affinity column(Pierce, Rockford, Ill.).

Example 2 Specificity of Anti-PDEF Antibody by Western Blotting andImmunohistochemistry

As shown in Panel A of FIG. 2, anti-PDEF antibody reacted specificallywith a 46 kD band in the MCF-7 breast tumor cell line, but not with theSKBR3 breast tumor cell line or the non-breast tumor cell lines Hela andU937. Also, the antibody reacted strongly with recombinant PDEF proteinrun as control. Further, the antibody showed specific nuclear stainingof tumor cells in the MCF-7 breast tumor cell line (FIG. 2, panel B),and its prior incubation with PDEF1-104 peptide eliminated the stainingFurthermore, screening of the tissue sections from a primary breastcarcinoma (FIG. 2, Panel C) and a primary prostate carcinoma (FIG. 2,Panel D) showed specific staining of the epithelial tumor cells, aresult consistent with epithelial cell specific expression of PDEF mRNA.

Example 3 Transfection of PDEF-Lacking MCF12-A Cell Line with PDEFInduces Reactivity with Antibody

Specificity of the anti-1-104 antibody for PDEF was further tested bytransfecting PDEF-lacking MCF-12A cell line with PDEF expressionplasmid. As shown in FIG. 3, only the PDEF-transfected MCF-12A cells butnot vector-transfected MCF-12A cells showed reactivity with ourantibody.

Example 4 Screening of Normal Human Tissues Further Validates PDEFSpecificity of the Antibody of the Present Invention

Previous work from Inventor's lab showed highly restricted expression ofPDEF mRNA in normal human tissues that was primarily limited to normalprostate and trachea (3). To determine whether PDEF protein expressioncorresponds with PDEF mRNA expression, tissue sections from a panel ofnormal human tissues were screened for PDEF protein expression usingInventor's antibody. The data showed that strong expression of PDEFprotein was present in the normal prostate tissue (FIG. 4, panel A) anda somewhat weaker expression in the normal bronchus/trachea tissue (FIG.4, panel B). Other normal human tissues including brain, heart, kidney,liver, lung, lymph nodes, ovary, pancreas, placenta, skeletal muscle,skin, spleen, stomach and thymus stained negative for PDEF proteinexpression. These results are in agreement with the corresponding dataon PDEF mRNA expression in the respective tissues (3); and furthervalidate the specificity of the anti-PDEF antibody of the presentinvention.

Example 5 PDEF Expression in Matched Pairs of Benign Breast and BreastTumor Tissues from Patients

Previous work from Inventor's lab showed over expression of PDEF mRNA inbreast tumor tissues in comparison to adjacent benign breast tissue fromindividual patients, and the level over expression in the tumor tissuevaried from a few-fold to as much as 88-fold (3). To determine whethersimilar over expression of PDEF protein occurs in breast tumors, PDEFprotein expression was analyzed in 9 matched pairs of adjacent benignbreast and tumor tissues, by using the antibody of the present inventiondescribed herein. It was found that in 90% (8 of 9) cases, the tumorsshowed an increase in the number of PDEF expressing epithelial cellsand/or the intensity of staining of such cells. The data are summarizedin Table 1 and representative photomicrographs are shown in FIG. 5.

TABLE 1 PDEF Expression in Matched Samples of Benign Breast and TumorTissues PDEF Expression Characteristics (Percent Positive Cells,Benign/Tumor Intensity of Staining) Pair Number Benign Tumor 1 0 40%, 1+2 0 20%, 2+ 3 40%, 2+ 60%, 2+ 4 30%, 2+  5%, 1+ 5  5%, 1+ 30%, 3+ 6  5%,1+ 20%, 2+ 7 0 80%, 2+ 8 15%, 1+ 65%, 1+ 9 0 60%, 2+

Together, the results shown in FIGS. 2-5 demonstrate the specificity ofthe anti-PDEF antibody of the present invention for PDEF, as well as itssuitability for use in immunohistochemical analysis of PDEF expressionin tissue sections from primary tumors from patients.

Example 6 Characteristics of PDEF Expression in Tumor Progression andUse of PDEF Expression Levels in Patient Prognosis and PatientStratification for Treatment

The validated PDEF antibody of the present invention was used todetermine the characteristics of PDEF protein expression in benigntissues and in primary tumor samples from breast, prostate, and ovariantumors from cancer patients. The results are described below.

PDEF expression is increased in progression from benign breast to ductalcarcinoma in situ (DCIS) and increased expression is maintained ininvasive carcinomas: Using the above antibody of the present invention,tissue micro arrays (TMAs) of breast tissues were screened for PDEFexpression. The data from this screening are presented in FIG. 6 and aresummarized below.

In benign breast tissue samples, 18% (11 of 62) scored positive for PDEFexpression. Of the remaining samples, 20 of 62 (32%) showed expressionlevels below the selected thresholds, and 31 of 62 (50%) lacked anydetectable PDEF expression.

For DCIS, 50% (23 of 46) of the samples scored positive for PDEFexpression, another 7 (15%) stained below the thresholds, and theremaining 16 of 46 (35%) showed no detectable staining.

A similar analysis of invasive ductal carcinoma (IDC) showed that 46%(30 of 65) of the invasive tumors were positive for PDEF expression. Ofthe remaining samples, 17% (11 of 65) showed staining below thethresholds and 24 of 65 (37%) lacked detectable staining.

In invasive lobular carcinoma (ILC), 51% (20 of 39) of the samplesscored positive for PDEF expression, another 5% (2 of 39) stained belowthe thresholds, and the remaining 44% (17 of 39) were negative.

In summary, the data presented in FIG. 6 show that, whereas 18% ofbenign breast tissues scored positive for PDEF, samples from DCIS, IDC,and ILC showed a much higher percentage of PDEF positive tumors, i.e.,50%, 46% and 51% of the screened samples, respectively.

Example 7 Progressively Increasing Fractions of Benign Prostate Tissue,PIN, and Prostate Carcinoma Samples Score Positive for PDEF Expression

Using the anti-PDEF antibody of the present invention, TMAs of prostatetissues were also stained and scored for PDEF expression. The data arepresented in FIG. 7 and are described below.

In the benign prostate tissues from cancer patients, 27% (79 of 290)scored positive for PDEF expression. Of the remaining samples, 24 of 290(9%) stained below the selected thresholds and another 187 of 290 (64%)lacked detectable PDEF expression.

For PIN samples, 36 of 109 (33%) scored positive for PDEF expression. Ofthe remaining, 9 of 109 (8%) stained below the thresholds and 64 out of109 (59%) showed no detectable staining.

A similar analysis of prostate carcinomas revealed that 40% (92 of 230)of the invasive carcinomas were positive for PDEF expression, another11% (25 of 230) showed staining below thresholds, and the remaining 113out of 230 (49%) samples lacked detectable staining.

In summary, the data presented in FIG. 7 support the following points:(i) increasingly higher percentage of samples scored positive for PDEFexpression in progression from benign prostate tissues (27% of samplespositive), to PIN lesions (33% of samples positive), and to prostatecarcinomas (40% of samples positive); and (ii) prostate carcinomasgenerally showed a higher percentage of cells staining positive for PDEFin comparison to PIN or benign tissue samples.

Example 8 Analysis of PDEF Expression in Matched Samples of CancerVersus Benign, Cancer Versus PIN, and PIN Versus Benign Showed FrequentIncreased PDEF Expression in Prostate Cancer

To further understand the characteristics of PDEF protein expression inbenign prostate and prostate carcinomas, PDEF expression was analyzed inmatched samples of prostate cancer and adjacent benign tissue or PIN.Overall, this analysis included 101 matched samples of cancer versus(v/s) benign, 41 matched samples of cancer v/s PIN, and 45 matchedsamples of PIN v/s benign. The data are compiled in Table 2. As shown inthis Table 2, in 68% (68 of 101) of the matched cancer v/s benign pairs,cancer specimens expressed higher levels of PDEF than the adjacentbenign prostate tissues. Similarly, in 70% (28 of 41) of the matchedcancer v/s PIN pairs, cancer showed higher PDEF expression than PIN. Incontrast, in PIN versus benign comparison, only 42% (19 of 45) PINlesions showed higher PDEF expression than the matched benign glandulartissues.

TABLE 2 PDEF Expression in Prostate Tissue: Matched Samples of Cancerv/s Benign, Cancer v/s PIN, and PIN v/s Benign Type of Number of Numberof Number of Match matched samples with samples with X v/s Y samplesmore* PDEF in X more* PDEF in Y P value Cancer v/s 101 68 (68%) 33 (32%)0.0006 benign Cancer v/s 41 28 (70%) 13 (30%) 0.0275 PIN PIN v/s 45 19(42%) 26 (58%) 0.3713 benign *More PDEF reflects higher percent ofPDEF-positive epithelial cells or higher intensity of staining or both.

In summary, the combined data from FIG. 7 and Table 2 show that PDEFexpression is frequently increased in the progression from benignprostate to cancer and from PIN to cancer. In contrast, there appearedto be no significant change in PDEF expression in progression frombenign prostate to PIN.

Example 9 PDEF Protein Expression is Undetectable in Normal Ovaries andCyst Adenomas and Frequently Increased in Tumors of Low MalignantPotential as Well as in Early and Late Stage Epithelial OvarianCarcinomas and Peritoneal Metastases

Using the antibody of the present invention, the various ovarian normaland tumor tissue samples were stained for PDEF expression. Therepresentative photomicrographs for each sample type are shown in FIG.8. A brief description of the results is provided below.

All 12 samples of normal ovaries lacked detectable staining for PDEFexpression. One representative photomicrograph is shown in Panel 2A.

Similarly, all 10 cases of benign serous adenoma were negative; arepresentative photomicrograph is shown in Panel 2B.

In ovarian tumors of low malignant potential, 6 of 17 (35%) cases scoredpositive for PDEF expression. The remaining cases lacked detectablestaining or stained weakly, and hence were scored negative. Arepresentative photomicrograph is shown in Panel 2C.

In early stage ovarian cancer, 5 of 19 (27%) cases were scored positivefor PDEF expression and the remaining scored as negative. Again, arepresentative photomicrograph is shown in Panel 2D.

Similarly, in the 15 cases of advanced stage ovarian cancer, each of theprimary ovarian tumors and its correlating peritoneal metastasis wasevaluated for PDEF expression. In 10 (67%) of these cases, both theprimary tumor and peritoneal metastases were negative for PDEFexpression. Of the remaining 5 (33%) cases that scored positive for PDEFexpression, one case stained similarly, while in another case theprimary tumor stained more strongly and with higher percentage ofpositive tumor cells than the peritoneal metastases. In the remainingthree cases, the peritoneal metastases stained more strongly and withhigher percentage of positive tumor cells than the primary tumor. Thestaining of the early and advanced cases of ovarian cancer isrepresented by photomicrograph in Panels 2D and 2E. These results arealso consistent with a role for PDEF in ovarian tumor progression.

Example 10 Induced Expression of PDEF in Low-Tumorigenic MCF-12A BreastCell Line Enhances its Tumorigenic Growth in Immunodeficient Mice

The frequent over expression of PDEF in breast tumors raised thequestion whether PDEF has a direct role in breast tumor development. Totest this idea, the low-tumorigenic MCF-12A cell line (that lacks PDEF)was transfected with PDEF expression plasmid, and found thatPDEF-expressing MCF-12A cells form progressively growing tumors withfaster kinetics, i.e., about 10 days in advance of the parentalPDEF-negative MCF-12A cells (see FIG. 9). These data show a criticalrole for PDEF in breast tumor development, and further support a rolefor PDEF in breast tumor progression.

Example 11 High PDEF Expression Predicts Poor Overall Survival forPatients with ER+ Breast Cancer

To seek independent evidence into the role of PDEF in breast cancer, theGEO and Oncomine databases (8) that contain the gene expressionprofiling and clinical outcome data from several previously publishedstudies (9-14) were searched, looking for any correlation between PDEFexpression levels and clinical outcome. Due to their adequate numbers,only ER+ breast cancer cases were included in this analysis. As shown inFIG. 10, in three independent datasets (9-11) high PDEF expression wasassociated with poor overall survival for patients. However, a similaranalysis of three other datasets (12-14) containing clinical data onrelapse and metastases showed no correlation between high PDEFexpression and early tumor relapse or distant metastases (12-14).Nevertheless, significant correlation between high PDEF expression andpoor overall survival for patients in three separate datasets providedcrucial evidence for an important role for PDEF in breast cancerprogression, and these results validate PDEF as a novelprognostic/predictive marker in breast cancer and a target fordeveloping novel therapeutics against this cancer.

Example 12 PDEF in Pathogenesis of Luminal Breast Cancer

PDEF expression was further examined in existing gene expressiondatasets (13, 15) to determine PDEF expression characteristics in breastcancer subtypes. As shown in FIG. 11, PDEF expression is specificallyrestricted to tumors arising in the luminal epithelial lineage. Incontrast, basal subtype of breast tumors lacked the expression of PDEF.On the basis of these observations, PDEF over expression appears to belinked to the pathogenesis of the luminal subtype of breast cancers thatcomprise more that 80% of the newly diagnosed breast cancers.

Example 13 High PDEF Expression Correlates with Intermediate to HighGleason Score in Prostate Cancer

A Gleason score is given to prostate cancer based upon its microscopicappearance. Cancers with a higher Gleason score are more aggressive andhave a worse prognosis. To determine any correlation of PDEF expressionwith Gleason Score (GS), low, intermediate, or high GS were assigned toprostate carcinomas according to the published criteria, and anyrelationship between their GS and PDEF expression status were analyzed.It was found that prostate cancers with intermediate GS showed thehighest correlation with PDEF expression, i.e., 77/159 (48%) tumorspositive for PDEF. In contrast, 24% (11/45) of high GS but only 15%(4/26) of low GS prostate carcinomas were positive for PDEF. Combiningintermediate and high GS tumors as one group (n=204), and comparing themwith low GS tumors as another group (n=26), 43% (88/204) of intermediateto high grade v/s and 15% (4/26) of low grade prostate carcinomas werepositive for PDEF, which was statistically significant (P<0.01).

Example 14 High PDEF Expression Also Shows Correlation with BiochemicalPSA Failure in Prostate Cancer Patients

Biochemical PSA failure is defined as three consecutive rises of PSA andis used as a surrogate end point indicative of disease recurrence andprogression in patients. To determine whether high PDEF expression inprostate tumors predicts PSA failure, patients from a study cohort forwhom consecutive PSA readings were available were selected.Specifically, patients with localized prostate cancer treated withradical prostatectomy were included in the study. PDEF expression wasscored for staining intensity (+1, +2, +3) and percentage of stainingcells. Product of the two indicators (staining score) was used for dataanalysis and tested for correlation with clinical information. Thisanalysis identified a group of patients with high PDEF expression whohave an increased risk for biochemical failure (FIG. 12; p=0.0472). In amultivariate analysis, high PDEF staining score was a predictor ofbiochemical failure that was independent of preoperative PSA, Gleasonsum, pathologic stage, and PDEF expression in the adjacent benignprostate. Together, these data support a role for PDEF in prostatecancer progression as well, and underscore its potential as a novelprognostic/predictive marker in prostate cancer and a target fordeveloping novel therapeutics against this cancer.

Example 15 PDEF as a Vaccine Against Breast and Ovarian Cancers

Due to primarily prostate limited expression of PDEF in normal humantissues, it was hypothesized that males would exhibit tolerance to PDEF.In contrast, females will mount a stronger immune response against PDEF,which should make PDEF a highly desirable vaccine against femalecancers, including breast and ovarian cancers. This hypothesis wastested in mice and the results are shown below.

Pse can Induce Specific Immunity in Female Mice but Weak Immunity inMale Mice

Briefly, groups of FVB female and male mice were immunized with Pseplasmid transfected dendritic cells (Pse-DC). As a positive control,groups of mice were also immunized with Her2/neu plasmid transfected DC(Her2/neu-DC), and additional groups as a negative control wereimmunized with vector plasmid transfected DC (vector-DC). Specific Tcell responses elicited in FVB male and female mice were analyzed byELIspot assay and representative data from two separate experiments areshown in FIG. 13.

The data in FIG. 13 show preferential immunogenicity of Pse in femalemice since male mice show barely detectable levels of T cell responseagainst Pse. The latter measurement is not due to general lack ofresponsiveness of male mice, since T cell response to Her2/neu was foundto be quite efficient, although relatively lower in comparison to femalemice.

To determine whether the preferential immunogenicity of Pse in femalemice is not specific to the FVB strain of mice, identical experiments inthe C57BL/6 strain of mice were performed. The data are shown in FIG.14. Overall, the results are quite similar to those seen in FVB mice,except that the responses of C57BL/6 mice are generally more robust thanFVB mice for both male and female mice. Nevertheless, the response ofmale mice to Pse remains much more muted than that of the female mice.

In summary, the results shown in FIGS. 13 and 14 are highly novel andinteresting and Pse is the first example known hereby of a putativebreast tumor antigen that shows preferential immunogenicity in femalemice. These data strongly suggest that PDEF will be similarlyimmunogenic in breast cancer patients and support the development ofPDEF-based vaccines for treatment of breast cancer in accordance withthe present invention.

REFERENCES CITED

Citation of a reference herein shall not be construed as an admissionthat such reference is prior art to the present invention. Allreferences cited herein are hereby incorporated by reference in theirentirety. Below is a listing of references cited herein with referencenumber indicators:

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Although preferred embodiments have been depicted and described indetail herein, it will be apparent to those skilled in the relevant artthat various modifications, additions, substitutions, and the like canbe made without departing from the spirit of the invention and these aretherefore considered to be within the scope of the invention as definedin the claims which follow.

1. An isolated antibody or antigen-binding fragment thereof thatspecifically binds with high affinity to at least a portion of a segmentof a human prostate-derived Ets transcription factor (PDEF), whereinsaid segment comprises: (a) amino acid residues 1-104 of SEQ ID NO:1;(b) amino acid residues 105-141 of SEQ ID NO:1; or (c) amino acidresidues 214-247 of SEQ ID NO:1.
 2. The antibody or antigen-bindingfragment thereof according to claim 1, wherein said antigen-bindingfragment is selected from the group consisting of an F(ab)₂ fragment, anFab′ fragment, an Fab fragment, and an Fv fragment.
 3. The antibody orantigen-binding fragment thereof according to claim 1, wherein saidantibody or antigen-binding fragment thereof is selected from the groupconsisting of a polyclonal antibody, a monoclonal antibody, and a singlechain antibody.
 4. The antibody or antigen-binding fragment thereof ofclaim 1, wherein said antibody or antigen-binding fragment thereof isdetectably labeled.
 5. The antibody or antigen-binding fragment thereofof claim 4, wherein the detectable label is selected from the groupconsisting of a radioisotope, an affinity label, an enzymatic label, afluorescent label, and a paramagnetic atom.
 6. The antibody orantigen-binding fragment thereof according to claim 1, wherein theantibody or antigen-binding fragment thereof exhibits: (a) strongstaining intensity as determined in an immunohistochemical assay withthree or less of the normal tissues being selected from the groupconsisting of prostate gland tissue, salivary gland tissue, andtrachea/bronchus tissue; and (b) negative staining intensity asdetermined by an immunohistochemical assay with three or more tissuesselected from the group consisting of adrenal gland tissue, blood, braintissue, bone marrow, heart tissue, liver tissue, lung tissue, lymph nodetissue, kidney tissue, ovary tissue, placenta tissue, spleen tissue,skeletal muscle tissue, thymus tissue, and testis tissue.
 7. A hybridomathat produces the antibody according to claim 1, wherein said antibodyis a monoclonal antibody.
 8. (canceled)
 9. (canceled)
 10. A vaccine forimmunizing an individual against a cancer disease associated withpositive expression of PDEF, said vaccine comprising: (a) a polypeptidecomprising a PDEF fragment that is effective to induce an immuneresponse to PDEF in the individual, wherein said PDEF fragmentcomprises: (i) an amino acid sequence selected from the group consistingof SEQ ID NO:2, SEQ ID NO:3, and SEQ ID NO:4; (ii) an amino acidsequence having at least 8 continuous residues from SEQ ID NO:2, SEQ IDNO:3, or SEQ ID NO:4; or (iii) two or more amino acid sequences havingat least 8 continuous residues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQID NO:4; and (b) a pharmacologically acceptable carrier or adjuvant. 11.The vaccine according to claim 10 further comprising a nanoparticlevaccine comprising a peptide of at least 8 continuous residues from SEQID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.
 12. The vaccine according toclaim 10, wherein said cancer disease is selected from the groupconsisting of breast cancer, prostate cancer, ovarian cancer,endometrial cancer, colon cancer, and cervical cancer.
 13. A method forimmunizing an individual against a cancer disease associated withpositive PDEF expression, said method comprising: administering thevaccine according to claim 10 into the individual, wherein saidindividual is at high risk for, predisposed to, susceptible to, and/ordiagnosed with said cancer disease associated with positive PDEFexpression.
 14. The method according to claim 13, wherein said cancerdisease is selected from the group consisting of breast cancer, prostatecancer, ovarian cancer, endometrial cancer, colon cancer, and cervicalcancer.
 15. A viral or plasmid expression vector comprising: anucleotide sequence that is operably linked to a promoter and thatencodes an antigen, wherein said antigen is a PDEF fragment comprising:(i) an amino acid sequence selected from the group consisting of SEQ IDNO:2, SEQ ID NO:3, and SEQ ID NO:4; (ii) an amino acid sequence havingat least 8 continuous residues from SEQ ID NO:2, SEQ ID NO:3, or SEQ IDNO:4; or (iii) two or more amino acid sequences having at least 8continuous residues from SEQ ID NO:2, SEQ ID NO:3, and/or SEQ ID NO:4.16. (canceled)
 17. A method for immunizing an individual against acancer disease associated with positive PDEF expression, said methodcomprising: administering a vaccine to the individual, wherein saidindividual is at high risk for, predisposed to, susceptible to, and/ordiagnosed with said cancer disease associated with positive PDEFexpression, and wherein said vaccine comprises: (a) a viral or plasmidexpression vector according to claim 15, and (b) a pharmacologicallyacceptable carrier or adjuvant.
 18. The method according to claim 17,wherein said cancer disease is selected from the group consisting ofbreast cancer, prostate cancer, ovarian cancer, endometrial cancer,colon cancer, and cervical cancer. 19-27. (canceled)
 28. A method oftreating or preventing a disease characterized by growth of tumor cellsexpressing PDEF, said method comprising: administering to a subject avaccine according to claim 10, thereby inducing T cell immunity thatinhibits growth of tumor cells that express PDEF.
 29. A method oftreating or preventing a disease characterized by growth of tumor cellsexpressing PDEF, said method comprising: administering to a subject avaccine comprising: (a) a viral or plasmid expression vector accordingto claim 15, and (b) a pharmacologically acceptable carrier or adjuvant,thereby inducing T cell immunity that inhibits growth of tumor cellsthat express PDEF.
 30. (canceled)
 31. (canceled)
 32. (canceled)
 33. Amethod for boosting immunity of a cancer patient to a cancer diseaseassociated with positive expression of PDEF, said method comprising: (a)obtaining a tissue sample from the cancer patient, wherein said tissuesample is suspected of comprising cancer tumor tissue; (b) contactingthe tissue sample with the antibody or antigen-binding fragment thereofeffective to allow for measuring the level of PDEF expression in thetissue sample, wherein said antibody or antigen-binding fragment thereofspecifically binds with high affinity to at least a portion of a segmentof a human prostate-derived Ets transcription factor (PDEF), whereinsaid segment comprises: (i) amino acid residues 1-104 of SEQ ID NO:1;(ii) amino acid residues 105-141 of SEQ ID NO:1; or (iii) amino acidresidues 214-247 of SEQ ID NO:1; (c) measuring the level of PDEFexpressed in the tissue sample using an immunohistochemical assay,whereby positive expression of PDEF indicates that the patient is inneed of an additional immunization against PDEF; and (d) providing thepatient with a vaccine according to claim 10 under conditions effectiveto boost immunity of the cancer patient to the cancer disease associatedwith positive expression of PDEF.
 34. The method according to claim 33,wherein said tissue sample is selected from the group consisting ofbreast tissue, ovarian tissue, endometrial tissue, colon tissue, andcervical tissue.
 35. The method according to claim 33, wherein saidcancer disease is selected from the group consisting of breast cancer,ovarian cancer, endometrial cancer, colon cancer, and cervical cancer.